Structural and functional characterization of the c-terminal domain of the ecdysteroid phosphate phosphatase from bombyx mori reveals a new enzymatic activity.
Here, we present the crystal structure of the ecdysone phosphate phosphatase (EPPase) phosphoglycerate mutase (PGM) homology domain, the first structure of a steroid phosphate phosphatase. The structure reveals an alpha/beta-fold common to members of the two histidine (2H)-phosphatase superfamily with strong homology to the Suppressor of T-cell receptor signaling-1 (Sts-1 PGM) protein. The putative EPPase PGM active site contains signature residues shared by 2H-phosphatase enzymes, including a conserved histidine (His80) that acts as a nucleophile during catalysis. The physiological substrate ecdysone 22-phosphate was modeled in a hydrophobic cavity close to the phosphate-binding site. EPPase PGM shows limited substrate specificity with an ability to hydrolyze steroid phosphates, the phospho-tyrosine (pTyr) substrate analogue para-nitrophenylphosphate ( pNPP) and pTyr-containing peptides and proteins. Altogether, our data demonstrate a new protein tyrosine phosphatase (PTP) activity for EPPase. They suggest that EPPase and its closest homologues can be grouped into a distinct subfamily in the large 2H-phosphatase superfamily of proteins.
Chen
Yunting
Y
Department of Physiology and Biophysics, Stony Brook University, Basic Sciences Tower, Stony Brook, New York 11794-8661, USA.
Jakoncic
Jean
J
Wang
Jin
J
Zheng
Xiliang
X
Carpino
Nick
N
Nassar
Nicolas
N
D000818:Animals; D012831:Bombyx / Q000201:enzymology*; D002352:Carrier Proteins / Q000737:chemistry; D002384:Catalysis; D020134:Catalytic Domain / Q000502:physiology; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry*; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry*; D040681:Structural Homology, Protein
D002352:Carrier Proteins; D019476:Insect Proteins; C476613:ecdysteroid-phosphate phosphatase; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; C489397:UBASH3B protein, human